Ventilation grid



FIG. 1 is a perspective view of a ventilation grid showing a first embodiment of our new and ornamental design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a perspective view of a second embodiment of our design;

FIG. 6 is a front view of FIG. 5;

FIG. 7 is a rear view of FIG. 5; and,

FIG. 8 is a side view of FIG. 5. 

CLAIM The ornamental design for a ventilation grid, as shown. 